1. Industrial Field of Utilization
The present invention provides a saponified ethylene-vinyl acetate copolymer composition insuring improved oxygen barrier property and markedly improved physical properties, for example stretchability, film-forming property and other moldability and flexibility.
2. Prior Art
Saponified ethylene-vinyl acetate copolymers in general are excellent in various properties such as oxygen barrier property, mechanical strength, etc. and, as such, have found application in many uses such as film, sheet, container material, textile fiber and so on. However, this saponified copolymer gives rise to a variation in product thickness in the molding process for manufacture of film or sheet, with the consequent decrease in the marketability of the product, and because of the deficiency in stretchability and flexibility, gives rise to uneven stretching in deep-drawing and other processes involving a stretching force or pinholes in use of the product, thus imposing serious limitations on its application as a packaging raw material.
To cope with these drawbacks, it has been attempted to laminate a water-proof resin material such as a polyolefin film to a saponified ethylene-vinyl acetate copolymer sheet or improve stretchability and flexibility of the molding by incorporating a polyolefin in the saponified copolymer.
3. Problems that are to be Solved
However, the former method requires a laminating procedure as an essential step and the latter method does not overcome the drawbacks radically, either. Thus, the compatibility between the saponified ethylene-vinyl acetate copolymer and said polyolefin is not necessarily good enough and despite many efforts to overcome this disadvantage, the results are not as satisfactory as desired. Thus, the prior art technologies are not successful enough to improve the uniformity of film thickness, stretchability and flexibility of the saponified ethylene-vinyl acetate copolymer while upholding its inherent characteristics.